广义连续格的同态

引进和研究了广义连续格的下同态和上同态，建立了广义代数格紧元素之间的映射扩充为下同态的充要条件。     

Three-dimensional modelling of wood fracture in mode I,perpendicular to the grain direction at fibre level

Abstract

A coupled experimental and numerical modelling approach was used to investigate the mechanism of softwood fracture at the fibre level. First, a three-dimensional mixed lattice–continuum fracture model was developed to investigate the mechanism of wood fracture, taking into account the porosity of its structure and its heterogeneities at the fibre level. The critical volumes in the specimen where crack propagation was more probable were modelled by a lattice that could show the alternation of earlywood and latewood fibres, and the other regions were considered as the continuum medium. The proposed model was used to investigate the mode I fracture of a small softwood sample in RL orientation. Secondly, a method was developed for microscopic observation of the crack trajectory and investigating the mechanism of initiation and propagation of cracks. This approach was used for microscopic investigation of the fracture behaviour of spruce specimens in mode I and RL orientation. The results of the numerical study were compared with the experimental results. The prepeak and postpeak behaviour of the obtained stress–displacement curve and also the crack opening trajectory in cross-section and longitudinal section in the model and experiments were in good agreement. Both the model and the microscopic observation showed that in mode I fracture and RL orientation, the main trajectory of the crack propagates in the earlywood ring.     

Balanced designs for two-component competition experiments

Summary Many two-variety competition experiments have plants of the two varieties systematically arranged on a triangular lattice of hill plots. Designs, balanced in a certain sense, are introduced and their advantages explained. An example of such a design is presented and compared with one of a more conventional nature.     

完全有素的乘法模和网

若 R是带单位元的交换环 ,M是完全有素的乘法模 ,则 :(1 )映射 φ:P PM是从Spec(R)到 Spec(M)的双射 ;(2 ) Zariski拓扑空间 (Spec(R) ,T)和 Stone拓扑空间 (Spec(R*M) ,T*M)同胚 ;(3 ) (R*M,λ)构成 R的一个网。     

格上拓扑的比较

对格上的Ｃ－拓扑，Ｎ－拓扑，Ｌ－拓扑，Ｏ－拓扑以及Ｉ－拓扑的精细进行了比较，得到了一些新结果。     

Balanced designs for two-component competition experiments on a square lattice

Summary When two-component competition experiments are performed using systematic arrangements of hill plots on a square lattice, it is desirable for some purposes for the design to posses a certain balance property. A set of design strings is presented, any of which generates in a simple way an efficient balanced design. An example of such a design is discussed in relation to a more usual equal proportion mixture design.     

Review on the Preparation and Application of Carbon Membrane

Based on structure analysis software ANSYS, a non-linear complete-process analysis of stability behavior of single-layer latticed domes with different span and different rise-span ratio and different section is carried out. The effect of unsymmetrical loading distribution to the stability behavior of single layer latticed domes with various parameters is also analyzed. Some important conclusions are acquired and can be used as guidance to engineering design.     

基于三维X-CT图像的结皮土壤孔隙结构特征与渗透率

地表结皮广泛存在于干旱半干旱地区的表层土壤,对水土保持和生态环境有着重要的影响.该研究采用X射线断层扫描成像技术(X-CT)和图像分析方法,获取并分析了3个含表层结皮的土样(孔隙率分别为0.196、0.144和0.093)三维孔隙结构特征,并利用格子玻尔兹曼方法计算了各土样沿深度方向不同土层的渗透率.孔隙结构分析发现,...     

Stability Behavior of Shuttle-Shaped Steel Lattice Columns With Bending Moment

The stability behavior of shuttle-shaped steel lattice columns subject to combined axial force and bending moment was examined through elastic buckling analysis and geometrically and materially nonlinear analysis. Firstly, the concept of section stiffness variation ratio is proposed for shuttle-shaped lattice columns and the elastic buckling behavior is discussed. Then, the effect of bending moment on the stability behavior of lattice columns is investigated, with the emphasis on the development of axial stress, bending stress and shear stress. The influence of column component spacing and diaphragm thickness on the stability bearing capacity is also analyzed. It is shown that the elastic buckling mode of the lattice column is dependent on its section stiffness variation ratio; for lattice columns with C-shaped buckling mode, the reduction in stability bearing capacity caused by bending moment is smaller than that of columns with S-shaped buckling mode; the maximum stability bearing capacity of the lattice column can be achieved by adjusting the column component spacing, and the spacing corresponding to the maximum capacity is basically consistent with the critical spacing for transformation of C-shaped buckling mode and S-shaped mode; and it is more effective to increase the thickness of columns with S-shaped buckling mode to get larger bearing capacity.     

The 13 Bit Lattice Gas Automata Model with Polyvelocity and Regular Hexagonal Grid

The 13 bit lattice gas automata model with polyvelocity and regular hexagonal grid has been introduced. By simulating typical flow pass cylinder, the correctness and validity of the model have been verified.